Wireless Local Area Networks (“WLANs”) enable communications via mobile devices such as laptop computers. However, the tools and methods for testing WLANs and associated mobile devices have not matured at the same pace as those associated with wired technologies such as Ethernet. One factor that contributes to this situation is that wireless devices tend to be more complex than comparable wired systems because the wireless medium is inherently unreliable. Further, testing wireless networks requires special considerations to avoid interference from other wireless systems not involved in the test. Further, WLAN protocols have not yet fully matured, and are often in a state of flux because of ongoing standards activities.
One of the most difficult WLAN functions to test is handoff (sometimes referred to as “roaming”). Because WLAN clients are typically mobile, it is possible for a WLAN client to move out of range of the access point with which it is communicating. When this occurs the client must switch its association to another access point, if the client moves into range of another access point. Disassociating with one access point in favor of another access point is referred to as “handoff.” Current methods for testing handoff include open air testing, connecting the wireless equipment through cables, and assembling test setups in RF-shielded rooms. However, the current methods are impractical for testing handoff in complex WLANs in which many devices may simultaneously be in motion, and this is a problem.
The need for a solution to the problem of testing handoff in complex WLANs has recently become more acute due to proposals to support voice communications on WLANs. For example, the IEEE 802.11™ Working Group is presently working to further enhance the standard by adding features designed to facilitate handoff by decreasing time required for handoff. This feature is intended to enable wireless LANs to support voice handsets and other multimedia streaming applications. Further, because the coverage area for an access point in a WLAN is relatively small, handoffs can occur frequently. Therefore, there is a need to test handoff in complex WLANs in which many devices may be simultaneously in motion.